GB/T 846-2017Cross-recessed countersunk (flat) head tapping screws (English PDF)

Foreword

This Standard is one of the serial national standards of "Tapping Screws", such series

include.

--- GB/T 845 Cross-Recessed Pan Head Tapping Screws;

--- GB/T 846 Cross-Recessed Countersunk (Flat) Head Tapping Screws;

--- GB/T 847 Cross-Recessed Raised Countersunk Head Tapping Screws;

--- GB/T 2670.1 Hexalobular Socket Pan Head Tapping Screws;

--- GB/T 2670.2 Hexalobular Socket Countersunk Head Tapping Screws;

--- GB/T 2670.3 Hexalobular Socket Raised Countersunk (Oval) Head Tapping

Screws;

--- GB/T 5282 Slotted Pan Head Tapping Screws;

--- GB/T 5283 Slotted Countersunk Head Tapping Screws;

--- GB/T 5284 Slotted Raised Countersunk Head Tapping Screws;

--- GB/T 5285 Hexagon Head Tapping Screws;

--- GB/T 9456 Cross-Recessed Hexagon Head Tapping Screws with Indentation;

--- GB/T 13806.2 Fasteners for Fine Mechanics - Cross-Recessed Tapping Screws

- Scrape Point;

--- GB/T 16824.1 Hexagon Head Tapping Screws with Collar;

--- GB/T 16824.2 Hexagon Flange Head Tapping Screws.

This Standard was drafted as per the rules specified in GB/T 1.1-2009.

This Standard replaced GB/T 846-1985 Cross-Recessed Countersunk (Flat) Head

Tapping Screws; compared with GB/T 846-1985, this Standard has the major technical

changes as follows.

--- Increased Type-R (see Figure 1 and Table 1);

--- Add general technical conditions as per GB/T 16938 (see Clause 2, Table 2);

--- For steel screws, add the untreated and non-electrolytically applied zinc flake

coating technical requirements as per GB/T 5267.2 (see Table 2);

Cross-Recessed

Countersunk (Flat) Head Tapping Screws

1 Scope

This Standard specifies the type and dimension, technical conditions and marking of

cross-recessed countersunk (flat) head tapping screws.

This Standard is applicable to the cross-recessed countersunk (flat) head tapping

screws with Thread Specification of ST 2.2 ~ ST 9.5, and Product Grade A.

2 Normative References

The following documents are essential to the application of this document. For the

dated documents, only the versions with the dates indicated are applicable to this

document; for the undated documents, only the latest version (including all the

amendments) are applicable to this document.

GB/T 90.1 Fasteners - Acceptance Inspection (GB/T 90.1-2002, idt ISO

3269.2000)

GB/T 90.2 Fasteners - Marking and Packaging

GB/T 944.1 Cross Recesses for Screws (GB/T 944.1-1985, eqv ISO 4757.1983)

GB/T 1237 Designation System for Fasteners (GB/T 1237-2000, eqv ISO

8991.1986)

GB/T 3098.5 Mechanical Properties of Fasteners -Tapping Screws (GB/T 3098.5-

2016, ISO 2702.2011, MOD)

GB/T 3098.21 Mechanical Properties of Fasteners - Stainless Steel Tapping

Screws (GB/T 3098.21-2014, ISO 3506-4.2008, MOD)

GB/T 3103.1 Tolerances for Fasteners - Bolts, Screws and Nuts (GB/T 3103.1-

2002, idt ISO 4759-1.2000)

GB/T 5267.1 Fasteners - Electroplated Coatings (GB/T 5267.1-2002, ISO

4042.1999, IDT)

GB/T 5267.2 Fasteners - Non-Electrolytically Applied Zinc Flake Coatings (GB/T

......